We plan to determine the structure of hemoglobin A1c and the other minor components, A1a and A1b; to work out the mechanism for the synthesis of these hemoglobins and to develop a reliable method for measuring HbA1c on multiple blood samples. During the next year we hope to study the reaction of hemoglobin with sugar phosphates and determine whether G6P hemoglobin is a precursor of HbA1c. In addition we hope to establish the structure of Hbs A1b and ascertain whether HbA1a is identical to G6P hemoglobin. BIBLIOGRAPHIC REFERENCES: Bunn, H.F., Haney, D.N., Kamin, S., Gabbey, K.G. and Gallop, P.M.: The biosynthesis of hemoglobin A1c in vitro and in-vivo. J. Clin. Invest. Volume 57, pp. 1652-1659, June 1976. Haney, D.N., and Bunn, H.F.: Glycosylation of hemoglobin in vitro: Affinity labeling of hemoglobin by glucose-6-phosphate. Proc. Natl. Acad. Sci., U.S.A. Vol. 73 No. 10, pp. 3534-3538, October 1976.